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Aoyagi, Kazuhei; Sakurai, Akitaka; Niunoya, Sumio*
JAEA-Data/Code 2015-012, 171 Pages, 2015/09
JAEA-Data-Code-2015-012.zip:33.31MB
JAEA-Data-Code-2015-012.pdf:28.27MB
The objective of this report is to investigate the three dimensional stress state in the 250 m Niche off the West Shaft No.1 at the Horonobe Underground Research Laboratory. For the measurement, three 20.0m long boreholes were drilled. Hydraulic fracturing was applied as a stress measurement method. For the analysis, shut-in pressure of a transverse fractures, reopening pressure of longitudinal fractures and stress condition causing borehole breakouts were integrated into the equation; then stress state was calculated by inversion technique. As a result of the in situ stress state measurement around the experimental area, the orientation of the maximum principal stress was estimated to be ESE-WNW, dipping 70
from the vertical axis. The orientation of the minimum principal stress was NEN-SWS, dipping 60 from vertical axis. The orientation of the principal stresses is almost coincided with the direction of borehole breakouts and longitudinal crack induced in the boreholes. The values of the maximum and minimum principal stresses were 2.6 MPa and 2.1 MPa, respectively.
Aoyagi, Kazuhei; Sakurai, Akitaka; Niunoya, Sumio*
JAEA-Data/Code 2015-011, 182 Pages, 2015/09
JAEA-Data-Code-2015-011.pdf:33.41MBJAEA-Data-Code-2015-011-appendix(CD-ROM).zip:41.95MB
The objective of this report is to investigate the three dimensional stress state in the 250 m Niche off the South Shaft No.1 at the Horonobe Underground Research Laboratory. For the measurement, three 20.0m long boreholes were drilled. Hydraulic fracturing was applied as a stress measurement method. For the analysis, shut-in pressure of a transverse fractures, reopening pressure of longitudinal fractures and stress condition causing borehole breakouts were integrated into the equation; then stress state was calculated by inversion technique. As a result of the in situ stress state measurement around the experimental area, the orientation of the maximum principal stress is estimated to be between E-W and ENE-WSW, dipping almost horizontal direction. This result agrees well with the estimated orientation of the main principal stress, the location of the borehole wall breakouts in 10-E250-M01 and the orientation of the generated crack in 10-E250-M03. The value of the maximum principal stress was 3.97 MPa.
Kuwabara, Kazumichi; Sato, Toshinori; Sanada, Hiroyuki; Takayama, Yusuke
JAEA-Research 2015-005, 378 Pages, 2015/07
JAEA-Research-2015-005.pdf:125.5MBJAEA-Research-2015-005.zip:0.53MB
This report presents the results of following rock mechanical investigations conducted at the -500m Stage. (1) Laboratory tests using cores and block samples obtained at the -500m Stage. (2) In-situ stress measurement using Compact Conical-ended Borehole Overcoring (CCBO) method at the -500m Stage. (3) In-situ stress measurements using Differential Strain Curve Analysis(DSCA) method at the -500m Stage. (4) Development of rock mechanical model.
Morooka, Satoshi; Kawasaki, Takuro; Harjo, S.; Nakada, Nobuo*; Tsukada, Yuki*
no journal, ,
Harjo, S.; Gong, W.; Kawasaki, Takuro; Mao, W.; Ito, Tatsuya
no journal, ,
no abstracts in English